when drawing a line, we check if the line is only one point, to even draw a line

this fixes bug #709, but it's not quite good in my opinion (Stephan, please could you review?)


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@18050 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/servers/app/drawing/Painter/Painter.cpp

@@ -342,12 +342,22 @@ Painter::StrokeLine(BPoint a, BPoint b)
 			return _Clipped(touched);
 		}
 	}
+	
 	// do the pixel center offset here
-	a.x += 0.5;
-	a.y += 0.5;
-	b.x += 0.5;
-	b.y += 0.5;
-
+	// TODO review this :
+	// in case it's the same pixel, we offset differently to have something drawn
+	if (a == b) {
+		a.x += 0.25;
+		a.y += 0.25;
+		b.x += 0.75;
+		b.y += 0.75;
+	} else {
+		a.x += 0.5;
+		a.y += 0.5;
+		b.x += 0.5;
+		b.y += 0.5;
+	}
+	
 	agg::path_storage path;
 	path.move_to(a.x, a.y);
 	path.line_to(b.x, b.y);